drivers/iio/dac/max517.c

   1 /*
   2  *  max517.c - Support for Maxim MAX517, MAX518 and MAX519
   3  *
   4  *  Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/slab.h>
  23 #include <linux/jiffies.h>
  24 #include <linux/i2c.h>
  25 #include <linux/err.h>
  26
  27 #include <linux/iio/iio.h>
  28 #include <linux/iio/sysfs.h>
  29 #include <linux/iio/dac/max517.h>
  30
  31 #define MAX517_DRV_NAME "max517"
  32
  33 /* Commands */
  34 #define COMMAND_CHANNEL0        0x00
  35 #define COMMAND_CHANNEL1        0x01 /* for MAX518 and MAX519 */
  36 #define COMMAND_PD              0x08 /* Power Down */
  37
  38 enum max517_device_ids {
  39         ID_MAX517,
  40         ID_MAX518,
  41         ID_MAX519,
  42         ID_MAX520,
  43         ID_MAX521,
  44 };
  45
  46 struct max517_data {
  47         struct i2c_client       *client;
  48         unsigned short          vref_mv[8];
  49 };
  50
  51 /*
  52  * channel: bit 0: channel 1
  53  *          bit 1: channel 2
  54  * (this way, it's possible to set both channels at once)
  55  */
  56 static int max517_set_value(struct iio_dev *indio_dev,
  57         long val, int channel)
  58 {
  59         struct max517_data *data = iio_priv(indio_dev);
  60         struct i2c_client *client = data->client;
  61         u8 outbuf[2];
  62         int res;
  63
  64         if (val < 0 || val > 255)
  65                 return -EINVAL;
  66
  67         outbuf[0] = channel;
  68         outbuf[1] = val;
  69
  70         res = i2c_master_send(client, outbuf, 2);
  71         if (res < 0)
  72                 return res;
  73         else if (res != 2)
  74                 return -EIO;
  75         else
  76                 return 0;
  77 }
  78
  79 static int max517_read_raw(struct iio_dev *indio_dev,
  80                            struct iio_chan_spec const *chan,
  81                            int *val,
  82                            int *val2,
  83                            long m)
  84 {
  85         struct max517_data *data = iio_priv(indio_dev);
  86
  87         switch (m) {
  88         case IIO_CHAN_INFO_SCALE:
  89                 /* Corresponds to Vref / 2^(bits) */
  90                 *val = data->vref_mv[chan->channel];
  91                 *val2 = 8;
  92                 return IIO_VAL_FRACTIONAL_LOG2;
  93         default:
  94                 break;
  95         }
  96         return -EINVAL;
  97 }
  98
  99 static int max517_write_raw(struct iio_dev *indio_dev,
 100         struct iio_chan_spec const *chan, int val, int val2, long mask)
 101 {
 102         int ret;
 103
 104         switch (mask) {
 105         case IIO_CHAN_INFO_RAW:
 106                 ret = max517_set_value(indio_dev, val, chan->channel);
 107                 break;
 108         default:
 109                 ret = -EINVAL;
 110                 break;
 111         }
 112
 113         return ret;
 114 }
 115
 116 static int __maybe_unused max517_suspend(struct device *dev)
 117 {
 118         u8 outbuf = COMMAND_PD;
 119
 120         return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
 121 }
 122
 123 static int __maybe_unused max517_resume(struct device *dev)
 124 {
 125         u8 outbuf = 0;
 126
 127         return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
 128 }
 129
 130 static SIMPLE_DEV_PM_OPS(max517_pm_ops, max517_suspend, max517_resume);
 131
 132 static const struct iio_info max517_info = {
 133         .read_raw = max517_read_raw,
 134         .write_raw = max517_write_raw,
 135 };
 136
 137 #define MAX517_CHANNEL(chan) {                          \
 138         .type = IIO_VOLTAGE,                            \
 139         .indexed = 1,                                   \
 140         .output = 1,                                    \
 141         .channel = (chan),                              \
 142         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |  \
 143         BIT(IIO_CHAN_INFO_SCALE),                       \
 144 }
 145
 146 static const struct iio_chan_spec max517_channels[] = {
 147         MAX517_CHANNEL(0),
 148         MAX517_CHANNEL(1),
 149         MAX517_CHANNEL(2),
 150         MAX517_CHANNEL(3),
 151         MAX517_CHANNEL(4),
 152         MAX517_CHANNEL(5),
 153         MAX517_CHANNEL(6),
 154         MAX517_CHANNEL(7),
 155 };
 156
 157 static int max517_probe(struct i2c_client *client,
 158                         const struct i2c_device_id *id)
 159 {
 160         struct max517_data *data;
 161         struct iio_dev *indio_dev;
 162         struct max517_platform_data *platform_data = client->dev.platform_data;
 163         int chan;
 164
 165         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 166         if (!indio_dev)
 167                 return -ENOMEM;
 168         data = iio_priv(indio_dev);
 169         i2c_set_clientdata(client, indio_dev);
 170         data->client = client;
 171
 172         /* establish that the iio_dev is a child of the i2c device */
 173         indio_dev->dev.parent = &client->dev;
 174
 175         switch (id->driver_data) {
 176         case ID_MAX521:
 177                 indio_dev->num_channels = 8;
 178                 break;
 179         case ID_MAX520:
 180                 indio_dev->num_channels = 4;
 181                 break;
 182         case ID_MAX519:
 183         case ID_MAX518:
 184                 indio_dev->num_channels = 2;
 185                 break;
 186         default:  /* single channel for MAX517 */
 187                 indio_dev->num_channels = 1;
 188                 break;
 189         }
 190         indio_dev->channels = max517_channels;
 191         indio_dev->modes = INDIO_DIRECT_MODE;
 192         indio_dev->info = &max517_info;
 193
 194         /*
 195          * Reference voltage on MAX518 and default is 5V, else take vref_mv
 196          * from platform_data
 197          */
 198         for (chan = 0; chan < indio_dev->num_channels; chan++) {
 199                 if (id->driver_data == ID_MAX518 || !platform_data)
 200                         data->vref_mv[chan] = 5000; /* mV */
 201                 else
 202                         data->vref_mv[chan] = platform_data->vref_mv[chan];
 203         }
 204
 205         return iio_device_register(indio_dev);
 206 }
 207
 208 static int max517_remove(struct i2c_client *client)
 209 {
 210         iio_device_unregister(i2c_get_clientdata(client));
 211         return 0;
 212 }
 213
 214 static const struct i2c_device_id max517_id[] = {
 215         { "max517", ID_MAX517 },
 216         { "max518", ID_MAX518 },
 217         { "max519", ID_MAX519 },
 218         { "max520", ID_MAX520 },
 219         { "max521", ID_MAX521 },
 220         { }
 221 };
 222 MODULE_DEVICE_TABLE(i2c, max517_id);
 223
 224 static struct i2c_driver max517_driver = {
 225         .driver = {
 226                 .name   = MAX517_DRV_NAME,
 227                 .pm     = &max517_pm_ops,
 228         },
 229         .probe          = max517_probe,
 230         .remove         = max517_remove,
 231         .id_table       = max517_id,
 232 };
 233 module_i2c_driver(max517_driver);
 234
 235 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
 236 MODULE_DESCRIPTION("MAX517/518/519/520/521 8-bit DAC");
 237 MODULE_LICENSE("GPL");